expanding my ip pools
dave c
dhcp at gvtc.drakkar.org
Wed Nov 18 20:10:49 UTC 2015
Hello Leandro,
It looks like today you are not using the subnet declaration as intended. I think it would work
as well for you to have the subnet match the actual subnets in use on your vlan.
> shared-network Public {
> subnet 10.10.0.0 netmask 255.255.240.0 {
Here you are defining the netmask as a /20 and then you define pools as if they were a separate
subnet, complete with their own netmasks and routers.
>
> #10.10.1.0/24
> pool {
> range 10.10.1.2 10.10.1.254;
> option broadcast-address 10.10.1.255;
> option subnet-mask 255.255.255.0;
> option routers 10.10.1.1;
> }
>
Instead I would use the following:
shared-network Public {
subnet 10.10.0.0 netmask 255.255.255.0 {
option broadcast-address 10.10.0.255;
option subnet-mask 255.255.255.0;
option routers 10.10.0.11;
# notice no pool defined as no IP space allocated for DHCP management.
# likely this is your primary subnet in your vlan if all DHCP requests come from it.
}
subnet 10.10.1.0 netmask 255.255.255.0 {
option broadcast-address 10.10.1.255;
option subnet-mask 255.255.255.0;
option routers 10.10.1.1;
pool {
range 10.10.1.2 10.10.1.254
}
}
subnet 10.10.2.0 netmask 255.255.254.0 {
option broadcast-address 10.10.3.255;
option subnet-mask 255.255.254.0;
option routers 10.10.2.1;
pool {
range 10.10.2.2 10.10.3.254
}
}
## etc... with each of what you are calling "pools" today defined as a separate subnet
## inside your shared network.
## Then the two new subnets you are adding would be defined as follows:
subnet 10.10.96.0 netmask 255.255.248.0 {
option broadcast-address 10.10.103.255;
option subnet-mask 255.255.248.0;
option routers 10.10.96.1;
pool {
range 10.10.96.2 10.10.103.254;
}
}
subnet 10.10.104.0 netmask 255.255.248.0 {
option broadcast-address 10.10.111.255;
option subnet-mask 255.255.248.0;
option routers 10.10.104.1;
pool {
range 10.10.104.2 10.10.104.254;
}
## Btw, I notice that you only defined 253 IPs in this /21 of subnet space
} ## close the last subnet statement
} ## Eventually you would close the shared-network statememt
I've not tested the above in a dhcpd.conf file so it might have a minor typo, but I believe the
basic pattern to be correct. Also, by defining each of those subnets as "subnets", you could
probably drop the option subnet-mask and option broadcast-address statements. The option routers
is needed. I see from my own configs that I too define the options subnet-mask even though it's
defined as part of the subnet declaration. Could be stuff I inherited and not needed, but it's
certainly not breaking anything for me to have it defined... though when I get it wrong inside a
subnet declaration (forget to edit it when I copy a subnet and edit to a new size) it sets off
alarms and makes it not load new configs anymore :)
Dave
On 11/18/15 10:24, Leandro wrote:
> Hy guys, I would like to ask about how to expand my pool.
> So far I have a setting working ok, but I need to add a new prefix wich is not continuos and
> does not include the ip source of the dhcp requests.
>
> Requests came from ip 10.10.0.11.
> I need to add two segments:
> 10.10.96.0 /21
> 10.10.104.0 /21
>
> And here is my current share network setting:
>
> shared-network Public {
> subnet 10.10.0.0 netmask 255.255.240.0 {
>
> #10.10.1.0/24
> pool {
> range 10.10.1.2 10.10.1.254;
> option broadcast-address 10.10.1.255;
> option subnet-mask 255.255.255.0;
> option routers 10.10.1.1;
> }
>
> #10.10.2.0/23
> pool {
> range 10.10.2.2 10.10.3.254;
> option broadcast-address 10.10.3.255;
> option subnet-mask 255.255.254.0;
> option routers 10.10.2.1;
> }
>
> #10.10.4.0/22
> pool {
> range 10.10.4.2 10.10.7.254;
> option broadcast-address 10.10.7.255;
> option subnet-mask 255.255.252.0;
> option routers 10.10.4.1;
> }
>
> #10.10.8.0/21
> pool {
> range 10.10.8.2 10.10.15.254;
> option broadcast-address 10.10.15.255;
> option subnet-mask 255.255.248.0;
> option routers 10.10.8.1;
> }
> }
> }
>
>
> ######################################3
> This is what Im planning to do:
>
> shared-network Public {
> subnet 10.10.0.0 netmask 255.255.240.0 {
>
> #10.10.1.0/24
> pool {
> range 10.10.1.2 10.10.1.254;
> option broadcast-address 10.10.1.255;
> option subnet-mask 255.255.255.0;
> option routers 10.10.1.1;
> }
>
> #10.10.2.0/23
> pool {
> range 10.10.2.2 10.10.3.254;
> option broadcast-address 10.10.3.255;
> option subnet-mask 255.255.254.0;
> option routers 10.10.2.1;
> }
>
> #10.10.4.0/22
> pool {
> range 10.10.4.2 10.10.7.254;
> option broadcast-address 10.10.7.255;
> option subnet-mask 255.255.252.0;
> option routers 10.10.4.1;
> }
>
> #10.10.8.0/21
> pool {
> range 10.10.8.2 10.10.15.254;
> option broadcast-address 10.10.15.255;
> option subnet-mask 255.255.248.0;
> option routers 10.10.8.1;
> }
> }
> #####this is what I would add:
> subnet 10.10.96.0 netmask 255.255.240.0 {
>
> #10.10.96.0/21
> pool {
> range 10.10.96.2 10.10.103.254;
> option broadcast-address 10.10.103.255;
> option subnet-mask 255.255.248.0;
> option routers 10.10.96.1;
> }
>
> #10.10.104.0/21
> pool {
> range 10.10.104.2 10.10.104.254;
> option broadcast-address 10.10.111.255;
> option subnet-mask 255.255.248.0;
> option routers 10.10.104.1;
> }
>
>
> }
>
> }
>
> My concern is that the request ip source is not included in those segments , but should be
> enought that new segments are declared under a shared network statement.
> Other question is , after add those lines and restart service , already granted ips will be
> released ?
> Thanks for you wisdom.
> Leandro.
>
>
>
>
>
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--
Dave Calafrancesco
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